selftests/mm: skip the hugetlb-madvise tests on unmet hugepage requirements

Now that run_vmtests.sh does not guarantee that the correct hugepage count
is available, skip the hugetlb-madvise test if the requirements are not
met rather than failing.

Link: https://lkml.kernel.org/r/20240306223714.320681-4-npache@redhat.com
Signed-off-by: Nico Pache <npache@redhat.com>
Cc: Ben Hutchings <ben@decadent.org.uk>
Cc: Muchun Song <muchun.song@linux.dev>
Cc: Muhammad Usama Anjum <usama.anjum@collabora.com>
Cc: Shuah Khan <shuah@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

Author: PacheNico

tools/testing/selftests/mm/hugetlb-madvise.c

@@ -19,6 +19,7 @@
 #include <sys/mman.h>
 #include <fcntl.h>
 #include "vm_util.h"
+#include "../kselftest.h"
 
 #define MIN_FREE_PAGES	20
 #define NR_HUGE_PAGES	10	/* common number of pages to map/allocate */
@@ -78,7 +79,7 @@ int main(int argc, char **argv)
 	free_hugepages = get_free_hugepages();
 	if (free_hugepages < MIN_FREE_PAGES) {
 		printf("Not enough free huge pages to test, exiting!\n");
-		exit(1);
+		exit(KSFT_SKIP);
 	}
 
 	fd = memfd_create(argv[0], MFD_HUGETLB);